How to Backwash your Sand Filter


The sand filter is the only filter media that can be truly backwashed, making it the most user friendly filter. When backwashing, the water flow is reversed pushing up on the sand and releasing the dirt from its jagged surface.

TIP – never gauge how long to backwash on the site glass (clear glass/plastic jar on the side of the filter head.) While backwashing, discolored water runs through the site glass and clears quickly, only showing the dirt from top of the filter.

You should backwash your filter when the pressure is 8 to 10 psi higher than YOUR normal psi reading. In this every Pool Owner is special, having their own unique PSI reading/number. For example my psi reading is 12psi so when the pressure reaches 20psi I backwash my sand filter.

TIP – Your special PSI reading is the number on the pressure gauge after you have backwashed your filter for 3 minutes and rinsed for 30 seconds.

Hayward pool filter

Having a dirty filter (high psi reading) cleans your pool water more efficently by not allowing smaller particles to pass through the sand. But when your PSI reading is too high you may notice a lack of suction while trying to vacuum or poor circulation from low pressure from your return jet.

TIP – Never attempt to move the lever/handle on the filter head while the pump is running. By doing this costly damage can occur to the filter head.

Check both the skimmer and pump baskets, removing debris if necessary.

Backwashing Steps:

  • Turn the pump off
  • Move the lever/handle to backwash
  • Turn pump on and run for 3 minutes
  • Turn pump off
  • Move lever/handle to rinse
  • Turn pump on and run for 30 seconds
  • Turn pump off
  • Mover lever/handle to filter
  • Turn pump ON

By following the recommended time for backwashing you won’t need to backwash as frequently, thus allowing the sand to clean more efficiently and saving you water. A plus to those who rely on water from a well.

Remember to rinse! Rinsing for the 30 seconds after backwashing pushes the sand back in place clearing the filter of loose dirty water. If you don’t rinse you will have a dirty puff of water coming through the jet back into your clean pool.

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